Heart Rate Zone Calculator
Enter your age and resting heart rate to calculate your estimated maximum heart rate and the five heart-rate training zones you can use to pace recovery, fat-burning, aerobic, threshold, and maximal-effort workouts.
How this calculation works
This calculator uses the Karvonen (heart-rate-reserve) method. First it estimates your maximum heart rate with the classic formula Max HR = 220 − age. Then it subtracts your resting heart rate from that to get your heart-rate reserve (HRR), the range your heart actually works within between full rest and full effort.
Each training zone is a percentage band of HRR added back on top of your resting heart rate: Target HR = resting HR + (intensity % × HRR). Because it starts from your own resting HR rather than max HR alone, Karvonen zones are more personalized than simple percent-of-max-HR tables, especially for people with unusually low or high resting heart rates.
The five zones run from 50–60% (light recovery) up to 90–100% (maximal effort) of heart-rate reserve. Zone boundaries are rounded to the nearest whole beat per minute.
Worked example
The five heart rate zones explained
Each zone reflects a different percentage band of your heart-rate reserve and trains a different physiological system.
| Zone | % of HRR | Feel | Trains |
|---|---|---|---|
| Zone 1 | 50–60% | Very light, easy conversation | Recovery, warm-up, blood flow |
| Zone 2 | 60–70% | Light, can hold a conversation | Aerobic base, fat metabolism |
| Zone 3 | 70–80% | Moderate, breathing noticeably harder | Aerobic efficiency, endurance |
| Zone 4 | 80–90% | Hard, short sentences only | Lactate threshold, race pace |
| Zone 5 | 90–100% | Very hard, unsustainable | Maximal effort, speed, power |
220 minus age vs. the Tanaka formula
The 220 − age formula has been used since the 1970s because it is simple, but research since then shows it systematically overestimates max HR in younger adults and underestimates it in older adults. The Tanaka formula, 208 − 0.7 × age, was derived from a much larger dataset and is now preferred by many exercise physiologists as a better general-population estimate.
Both formulas are still just estimates. Genetics, fitness level, altitude, medications (especially beta blockers), heat, and stress can all shift your true maximum heart rate by 10–20 beats from any formula's prediction. If you know your measured max HR from a supervised max effort test, use that instead of an estimate.
Why the Karvonen method beats simple percent-of-max charts
- It accounts for your resting heart rate, so two people with the same max HR but very different fitness levels get different target zones.
- As cardio fitness improves and resting heart rate drops, your heart-rate reserve grows and your zones recalculate to reflect real fitness gains.
- It avoids under-training fit people and over-training unfit people, which flat percent-of-max-HR tables tend to do.
- It is the method most commonly recommended by exercise physiologists and used in cardiac rehabilitation programs.
Using zones in a real workout
Most training plans mix zones across a week rather than living in one: easy Zone 1–2 sessions for the bulk of weekly volume, occasional Zone 3 tempo work, and short, well-recovered Zone 4–5 intervals sprinkled in once or twice a week. This '80/20' pattern, mostly easy with a little hard, is common among endurance coaches because it builds aerobic capacity while limiting injury and burnout risk from too much high-intensity work.